The present invention generally relates to capsules for containing beverage ingredients, to a beverage producing system for use in connection with such capsules as well as to methods for producing beverages on the basis of ingredients contained in such capsules.
The background of the present invention is the field of capsules which contain beverage or other comestible (e.g. soup) ingredients. By means of an interaction of these ingredients with a liquid, a beverage or other comestibles, such as for example soups, can be produced. The interaction can be for example an extraction, brewing, dissolution, etc. process. Such a capsule is particularly adapted to contain ground coffee in order to produce a coffee beverage by having hot water under pressure enter the capsule and draining a coffee beverage from the capsule.
A capsule as shown in FR 2160634 relates to an apparatus for making coffee beverage from a cartridge in which a water injection device is placed hermetically against the upper side of the cartridge. The water injection device includes a seal which is applied on the upper rim of the capsule. However, the seal is part of the apparatus.
EP 0361569 A1 does not show a sealed capsule, but a coffee filter unit which is not sealed when placed into the coffee machine but simply press fitted in a cartridge casing, such that water can be poured on a filter paper provided at the open upper side of the coffee filter unit. To avoid spilling of water outside the filter unit's upper rim, the peripheral portion of a filter paper is clamped between the outer rim of the coffee filter unit wall and the surrounding wall of the machine. Such a design is a device which filters a beverage at atmospheric pressure and which is so not adapted to withstand the typical water injection pressure of e.g. more than 3 bars or even much higher pressure which reigns in the capsule when an espresso-style coffee is produced.
FR 2617389 describes a low cost filter cartridge adapted to be brewed at relatively low pressure in a beverage device. The body of the capsule is entirely made from injection-moulded plastic, preferably polypropylene as the main constituent of the capsule. The capsule has a flange like-rim made of the same material as the main constituent of the capsule which is thus crushed during closure of the device about the capsule. The capsule is combined to a brewing device which is a bayonet-like closure system which applies closure forces on the capsule's rim which depends on the tightening torque applied by the user. Therefore, the capsule's rim is crushed up to a point at which a certain seal effect can be obtained. One problem is that it is not possible with a simple flange-like rim, even with an increase of thickness, made of the same plastic material as the body of the capsule that normally requires a sufficient rigidity, to provide a seal effect which is sufficient to stop water or maintain a controlled internal pressure level, at the elevated relative pressure of extraction; i.e., within a pressure range sufficient to deliver an espresso-like coffee with crema. Furthermore, most modern beverage machines have closure devices that close at a predefined closure force and do not depend on the user's force therefore requiring an adaptation of the seal to the machine and not the opposite.
Systems and methods for obtaining fluid comestibles from substances containing capsules are for example known from EP-A-512470 (counterpart of U.S. Pat. No. 5,402,707).